A 100 kg skateboarder sits at the top of a 10 m halfpipe, ready to go down the ramp. What will be his velocity when he is 4 m off of the ground?

v = 10.85 m/s

Explanation:

We will apply the law of conservation of energy to the skateboarder. Neglecting the frictional effects, the law of conservation of energy can be written as:

where,

v = velocity of skateboarder = ?

g = acceleration due to gravity = 9.81 m/s²

Δh = change in height = 10 m - 4 m = 6 m

Therefore,

v = 10.85 m/s